Molded bobbin head coil assembly

ABSTRACT

A molded bobbin head coil assembly comprising a one piece molded bobbin which is divided into areas longitudinally by radially extending circumferential webs and coils and reactors wound and placed on the bobbin.

United States Patent 1 1 Van Zyl et a1.

[451 Aug. 5, 1975 1 1 MOLDED BOBBIN HEAD COIL ASSEMBLY [76] Inventors: Robert M. Van Zyl, 4074 Hillside Rd., Lafayette Hill, Pa. 19444; Joseph L. Molines, 765 Crooked Ln., Bridgeport, Pa. 19406 22 Filed: May 28, 1974 [21] Appl. No.: 473,854

[52] U.S. Cl 336/96; 336/208 [51] Int. Cl. HOIF 27/30 [58] Field of Search 336/96, 205, 198, 208; 310/199 [56] References Cited.

UNITED STATES PATENTS 429,583 6/1890 Pfannkuche 336/198 X 1.537.224 5/1925 Cohen 336/208 X 1,714.326 5/1929 Sne11..,.. 336/96 X 1,853,148 4/1932 Rigante 336/208 2,692,355 10/1954 Sickles et a1.. 336/198 X 3,008,108 11/1961 Baker et a1. 336/198 X 3,234,491 2/1966 Baur 1 336/198 3,526,712 9/1970 Drom 336/208 X 3,824,519 7/1974 Miller 336/208 X FOREIGN PATENTS OR APPLICATIONS 126,730 1/1901 Germany 336/96 Primary Examiner-Thomas J. Kozma Attorney, Agent, or Firm-R. S. Sciascia; Roy Miller [57] ABSTRACT A molded bobbin head coil assembly comprising a one piece molded bobbin which is divided into areas longitudinally by radially extending circumferential webs and coils and reactors wound and placed on the bobbin.

1 Claim, 5 Drawing Figures PATENTEUAUB 5|975 3, 898,600

' SHEET 1 I Fig. l

3.898,E5OO

PATENTEU AUG 5 I975 SHEET Fig. 3

Fig. 4

PATENTEUAUB 5|975 3, 898,600

SHEET 3 Fig. 5

MOLDED BOBBIN HEAD COIL ASSEMBLY CROSS-REFERENCE TO RELATED APPLICATION The present invention is intended foruse with a gyro such as set forth in co-pending US. application Ser. No. 473,855 filed May 28, 1974', by Robert M. VanZyl and Joseph L. Molines, titled OPTICAL GYROSCOPE ASSEMBLY, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the head coil assembly for a missile. Positioned within the interior of the head coil assembly is an optical gyroscope, such as disclosed in the co-pending application. The head coil assembly contains the reactor coils, precession coils, acquisition coils, motor coils, etc. which are used in conjunction with the gyro. I

2. Description of the Prior Art I Prior to the present invention, the head coil assembly used on the missiles required assembly in three stages; a reference motor coil potted assembly, a headcoil as sembly and finally the head coil potted assembly. The reference-motor coil potted assembly positioned the motor and reference coils and provided the inside contour of the final assembly and also established and mounting surfaces'for the precession coils. The entire assembly consisted of the reference-motor coil potted assembly, precession electrical caging coil, precession coil, precession and cancellation coil, acquisition precession cancellation coil and the terminal assembly. This much was potted to obtain a configuration which was used in a subsequent operation.

The head coil potted assembly consisted of the head coil assembly, gyro support molded assembly, saturable reactors and various connectors. These parts were assembled and aligned by means of a potting mold. In assembling the various components, the components were positioned on boresight test equipment prior to potting to achieve preliminary boresight position which was performed by adjusting the head coil assembly until the optical boresight requirement was achieved.

Components and fixture shifting caused by tempera-1 ture changes necessitated repetition of the timeconsuming boresight operation when the mold was hot, when potting was poured and both during and after cure. The procedure normally required repositioning the head coil five times to obtain a head coil potted assembly.

SUMMARY OF THE INVENTION The key feature of the present invention is a molded bobbin made from a hard plastic which is sectioned into areas upon which the various required electrical coils are wound and terminals and connectors mounted. Then the entire assembly is potted without requiring positioning jigs or fixtures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the molded assembly;

FIG. 2 is an end elevation of the entire assembly;

FIG. 3 is a section taken at 3-3 of FIG. 1;

FIG. 4 is a section taken at 4-4 of FIG. 2; and

FIG. 5 is a blow-up of the detail indicated by the broken-line enclosure of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT potting'removed for clarity. The molded bobbin 23 is formed such that there are three radially extending webs 30, 31 and 32 which define cavities 33, 34 and 35. The respective webs 30, 31 and 32 are ported as at 36,

37 and 38. Formed on the hub of the bobbin are upstanding portions 39, 40, 41 and 42. Upstanding portions 41 and 42 are ported as at 43 and 44 respectively.

"Also secured to the rear portion of the bobbin are terminal boards 45 and 46.

Theicavities'33, 34 and 35 are contoured to hold reactor coils coil 47 in cavity 33, reactor coil 48 in cavity 34 and reactor coils 49 and 50 in cavity 35. I As can be seen in FIG, 4, the bobbin 23 is made with radially extending flanges 60, 61 and 62 which in effect define: areas upon which various coils are wound. The various coils will not be identified in FIG. 4 as they are shown ingreater detail in FIG. 5.

Positioned in the throat of the bobbin is a motor and reference coil assembly 63 which is assembled beforehand and put in position prior to final potting. These are the coils that make the gyros spin in the ultimate assembly.

Metal insert 22 is shown in the drawing as having a uniform bore however, it is to be understood that the bore could be reduced at the end opening to the right in FIG. 4 and the remaining portion to the left in FIG. 4 threaded internally to accommodate a situation where the gyro assembly is threaded into the head coil assembly. However, in this embodiment the gyro assembly is secured to the forward end of the metal insert i.e., that end opening into the bell of the bobbin assembly screws.

A typical connection is shown at 63 between connector 26 and terminal board 46 in FIG. 4. It is to be understood that the various and sundry coils which are shown in detail in FIG. 5 have connections thereto which must be brought out to an exterior connector for connection.

Radially extending flanges 60 and 61 in the main body of the bobbin are relieved, as by a saw kerf, at 64, 65 and 66. This is to facilitate getting the wires from the most forward coils back to the terminal assemblies.

Potting compound 67 is indicated generally by the broken line cross hatching and it is noted that cavities 34 and 35 are the only ones potted. The remaining cavity at 33 is designed to accommodate a desiccant hous- FIG. 5 is a blow-up of FIG. 4 with cover it) removed. Positioned in the areas defined by flanges 60, 61 and 62 are various and sundry coils which are set forth below. Precession coils 70, 71 and electrical caging coils 72 are wound one on top of the other in the most forward area (to the left in FIG. 5). Precession coils 73 and 74 are wound between flanges 60 and 61 while precession coils 75, 76 and electrical cancellation coil 77 are wound next to flange 61 and rearwardly thereof. An acquisition coil 78 is wound around the exterior of the coils set forth above while an acquisition cancellation coil is wound at the periphery of the acquisition precession coil 78 and at one end thereof. Various unnumbered leads which go to the coils are shown by way of illustration.

In addition, the relieved portion formed by a port 80 is also shown for the purposes of clarity. Port 80 is shown in FIG. 3 in the end view of the bobbin assembly.

The various coils are insulated one from another by tape as at 81, 82 and 83. Tape 84 and 85 is provided as insulating means between the outer cover and the coils 78 and 79.

The motor and reference coil assembly is positioned in place prior to potting the whole assembly. The various coils are wound on the bobbin, the metal insert put in place as well as the terminal boards and connectors and reactors and then the final assembly potted.

The third cavity, cavity 33 defined by webs 30 and 32, is utilized as the desiccant chamber.

As a final step, a molded cover 1 l with breather holes and barriers is cemented over the desiccant cavity to retain the desiccant. Another one piece molded cover 86 snaps into the flanges on the bobbin and is cemented in place to cover the other two connector cavities. Cover 86 will also serve as a potting mold when a potting compound such as silastic RTV-60 is used.

Two materials were considered for molding the bobbin head coil in the present invention; diallyl Phthalate type STG and Fiberite FM 4005, type MFH. Both of the materials have the properties most desired for the head coil, that is, high heat distortion temperature and good dimensional stability.

It is to be understood that the head coil assembly may be designed for either use with standard electron tubes or transitors.

What is claimed is:

l. A molded bobbin head coil assembly for use in an optical gyroscope assembly comprising:

a thin-shelled rigid plastic bobbin having a central inner chamber;

said chamber terminating in a bell-shaped portion;

the length of the bell-shaped portion being approximately one-half the total length of the bobbin;

spaced apart radially extending flanges on the exterior of said bell-shaped portion extending around the circumference thereof;

another radially extending flange around the periphery of said bobbin at the end thereof remote from said bell-shaped portion;

a further radially extending flange around the periphery of said bobbin approximately midway of the length of said bobbin;

the spaces between all of said flanges defining compartments;

a motor and reference coil assembly positioned in the bell-shaped portion on the internal wall thereof and extending along the length of the wall of said bellshaped portion;

the other half of the chamber of said bobbin having substantially a uniform inner diameter;

a metal insert positioned within said other half and having an inner bore and in physical contact with a portion of the inner diameter of the other half of said bobbin;

reactor coils in the compartment between said another and a further radially extending flange;

precession coils, electrical caging coils, electrical cancellation coil, acquisition coil and acquisition cancellation coil positioned in the compartments between said first mentioned spaced apart radially extending flanges;

all of said coils being potted in place in said compartments defined by the flanges; and

covering means adapted to be snapped into place over the flanges to provide a smooth exterior surface for said assembly. 

1. A molded bobbin head coil assembly for use in an optical gyroscope assembly comprising: a thin-shelled rigid plastic bobbin having a central inner chamber; said chamber terminating in a bell-shaped portion; the length of the bell-shaped portion being approximately onehalf the total length of the bobbin; spaced apart radially extending flanges on the exterior of said bell-shaped portion extending around the circumference thereof; another radially extending flange around the periphery of said bobbin at the end thereof remote from said bell-shaped portion; a further radially extending flange around the periphery of said bobbin approximately midway of the length of said bobbin; the spaces between all of said flanges defining compartments; a motor and reference coil assembly positioned in the bellshaped portion on the internal wall thereof and extending along the length of the wall of said bell-shaped portion; the other half of the chamber of said bobbin having substantially a uniform inner diameter; a metal insert positioned within said other half and having an inner bore and in physical contact with a portion of the inner diameter of the other half of said bobbin; reactor coils in the compartment between said another and a further radially extending flange; precession coils, electrical caging coils, electrical cancellation coil, acquisition coil and acquisition cancellation coil positioned in the compartments between said first mentioned spaced apart radially extending flanges; all of said coils being potted in place in said compartments defined by the flanges; and covering means adapted to be snapped into place over the flanges to provide a smooth exterior surface for said assembly. 